Whereas there have been rapid advances in developing devices for medical imaging to guide surgery, relatively little attention has been paid to the basic perceptual-motor and cognitive processes involved in image-guided surgical intervention. Given the particular importance of mechanical properties of tissue in regulating surgical operation, I propose here a body of work using simulation techniques and psychophysical methods to investigate how humans perceive deformable tissue from the forces and torques arising from interactions, along with visible cues to deformation from an imaging tool. Achieving such an understanding and applying it to develop instruments and simulators to improve patient safety and facilitate training are long-term goals of my research. Under the support of an ongoing K99 award from NIBIB, I have developed a haptic simulation of viscoelastic tissue behavior, and used it to investigate the haptic (i.e. active touch) perception of deformable tissue. These research and technology development activities have laid a solid foundation for the planned ROO research. The proposed aims are (1) to complete the cun-ent testbed with simulated ultrasound visualization, (2) use the testbed to study the visual perception of viscoelastic tissue properties, and (3) to examine inter-sensory interaction involving haptic and visual cues in the perception of objects' viscoelastic properties. The results from the proposed research will be fed into the development of realistic rendering of deformable objects in virtual or augmented realities for medical applications like robotassisted tele-surgery or surgical simulators. I will continue collaboration with my K99 mentors (Drs. Roberta Klatzky, Ralph Hollis, George Stetten, and Kenji Shimada) and the NIBIB to insure successful completion of not only my research activities but also career development aims. I have accepted a tenure-track Assistant Professor position at the Arizona State University. This position, in conjunction with the current K99/R00 Award, will help me make the transition to independent research in my own multi-sensory research laboratory.